Aeroplane.



w. STEVENS. AEROPLANE.

APPLICATION FILED NOV-14, 1913.

Patented Ma 30,1916.

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W. STEVENS.

AEROPLANE. I APPLICATION FILED Nov. 4. 1913- Patented M y 30,1916-zsums-snm 2 W. STEVENS.

, ,AEROPLANE.

APPLICATION FILED NOV. 14, 1913.

Patented May 30, 1916.

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W. STEVENS.

' AEROPLANE.

APPLICATION FILED NOV. I4, I913.

Patented May 30, 1916.

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W. STEVENS.

AEROPLANE, APPLICATION FILED NOV. 14, 1913.

ISHEETS-SHEET 5.

Patented May 30,1916.

W. STEVENS. v

AEROPLANE.

APPLICATION FILED NOV. 14. 1913.

Patenteti- May 30, 1916.

7 SHEETS-SHEET 6.

W. STEVENS.

AEROPLANE. APPLICATION FILED NOV. 14, 1913.

Patented May 30,1916.

7 SHEETS-SHEET 7.

WILLIAM STEVENS, 0F BOSTON, MASSACHUSETTS.

' AEROPLANE.

To all *whom it may concern Be it known that I, WILLIAM STEVENS, acitizen of the United States, residing at Boston, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in Aeroplanes, of which the following is a specification.

My invention relates to aeroplanes and it has for its object to providean improved flying machine of this class.

Th invention consists of the novel fea tures of construction and mode ofoperation set forth in the following description and particularlypointed out and defined in the claims at the close thereof.

Figure 1 is a plan view of an aeroplane embodyingone form of myinvention. Fig. 2 is a side view of the machine shown in Fig. 1. Fig. 3is a front view, on smaller scale, of the machine shown in Fig. 1. Fig.4 is a diagrammatic perspective view illustrating the control for themachine shown in Figs. 1, 2 and 3. Fig. 5 is a plan view of an aeroplaneembodying other features of my invention. Fig. 6 is a side view of theaeroplane shown in Fig. 4. Fig. 7 is a front view of the aeroplane shownin Fig. 4. Fig. 8 is a section fore and aft through one of the wings.Fig. 9 is a sectional view of a portion of one of the wings takenlongitudinally thereof near the tip. Fig. 10 is a diagrammaticperspective view showing the control for the machine shown in Figs. 5, 6and 7. Fig. 11 is a detail of part of the control shown in Fig. 10. p

' In Figs. 1, 2 and 3 the two wings A and A are rigidly connected withthe body B near the front end of the latter and each not only extendsoutwardlv from the body but,

diagonally rearward also. Each wing is madeconcaved on its under sidethroughout its length from body to tip, and this concaved under surface1 is formed, longitudinally of the machine, on a parabolic curve such asis shown in Fig. 8. That is to say, any cross-sectional view of the wingtaken at any point between the body and the tip in a directionlongitudinally of the machine presents a parabolic concaved undersurface which, in order to provide for the neces sary lift, I arrange ordispose so that its chord sets at a positive incident flying angle asusual which may be of three degrees, or thereabout, to horizontal whenthe machine occupies its normal flying position as shown Specificationof Letters Patent.

Patented May 3d, 1916.

Application filed November 14, 1913. Serial No. 800,913.

that together they form a positive dihedral angle as viewed from thefront of the 1nachine. Fig. 3, the inner end of each wing being lowerthan the outer end thereof. As

herein shown this rearward upward slope is arranged at about an angle offive degrees to horizontal when the machine occupies its normal flyingposition. The dihedral angle formed by the two wings together insuresmarked lateral stability, while the diagonal disposition of the twowings as viewed in plan and their relation to the center of gravity ofthe machine which is in the plane yy, Fig; 1, affords a degree oflongitudinal stability which is greatly enhanced by the upward slope ofthe wings toward the rear. This upward slope ofthe wings toward the reartogether with their positive incident flying angle provides a compositepositive dihedral angle at each stability inthat direction. Inother'words the wings are shaped and disposed so that the two wingsjointly provide a lateral stabilizing positive dihedral angle while atthe same time the positive incident angle of each wing is combined withthe upward and rearward slope thereof to produce a positive longitudinalcomposite stabilizing dihedral angle in each wing.

Heretofore flying machines of this class have been constructed so thattheir wings formed a lateral positive dihedral stabilizing angle but sofar as I am aware I am the first to construct and dispose the wings sothat while flying each presents a positive longitudinal stabilizingdihedral angle with out at the same time causing the negative or rearside of said longitudinal angle to produce a negative drag. Also so faras I am aware I am the first to provide a construction wherein the sameslope of the wings which makes the lateral positive dihedral that whenthe machine is in flight the wind I passes diagonally across the top ofthe wing without being at all opposed by the up slope which forms thenegative side of the composite dihedral angle of each wing because ofthe positive incldent angle presented by all parts of the wing to thewind. This will be clear from Fig. 8.

When flyin horizontally the front edge of the parabo ic wing swirls thewind upward under the Wing throughout the length of the latter andcauses it not only-to produce the necessary lift but also to act frombelow against'the rear side of the longitudinal composite dihedralangle, or in other words against the slope of the wing, in a directionto assist the forward progress of the machine owing to the fact thatthere is, as is the case with all aeroplanes, a region of compressionunder the wing produced by the positive angle of .incidence, and thisregion of compression, with my machine, is of wave like form conformingto the slope of the wing which is the rearward side of the longitudinalpositive dihedral angle. This region of compression exists at all timesalong this slope, while the machine is aloft, and in my machine theslope of the wing is acted upon by said region of compression in amanner due to the direction of this slope to urge the machine forwardwhen flying under power and to compel the machine to descend in aforward direction in the event that it becomes powerless while aloft.Thus the elevating rudders C and C of the machine shown in Figs. 4 to10, or the wing flaps D and D of the machine shown in Figs. 1, 2 and 3,will not be resorted to to maintain fore and aft equilibrium to theextent that has heretofore been necessary, with a correspondinglessening of drag and a corresponding increase of speed as the result.

When, with either form of machine herein shown, the power is shut offduring horizontal flight, gravity tends to cause the machine to descendagainst the air beneath it, thus in effect producing an upward wind andthe region of compression referred to,

which acts in the manner just described.

Heretofore, under these circumstances, the upward wind acted only uponthe positive incident angle of the wings with the result that it tendedto force the machine rearward as it descended. This has been a featureof the constructions heretofore proposed which has been highlyobjectionable because of its resulting in many fatal accidents throughfalling backward, particularly when the machine became powerless whileascending. In my machine, while t'-e positive incident angle is actedupon by the upward wind as heretofore, the region of compression simultaneously acts upon the slope of the wings in a manner to oppose therearward action of the upward wind on the positive incident angle andthereby prevent the machine beingforced backward on a downward curve asheretofore. Thus should my machine become powerless while aloft, orwhile ascending, the opposing effects of the wind on the positiveincident angle of each wing, and on the sloping under surface thereof,automatically maintain the machine in its proper normal flying positionas it descends, compelling it to descend in a forward direction In itsnormally balanced condition. It will be clear, therefore, that these twoelements, viz., the positive-incident flying angle and the upward slope,cooperate at all times to automatically control the longitudinal balanceor equilibrium of the machine and to prevent rearward falling movement.

In the event that either machine herein shown becomes powerless whileflyin against a strong head wind the longitudina composite dihedralangles of the wings will hold the machine balanced longitudinally.

while the lifting effects of the wind on the wings will, if the wind besufficiently strong, counterbalance the weight of the machine or liftit. If, under these circumstances, the wind is not strong enough toproduce sufficient lift to support the weight of the machine, then thelatter will be compelled to glide downward in a forward direction whilethe longitudinal composite dihedral angle maintains the machinebalanced'longitudinally.

Since each diagonal wing is formed with a parabolic concaved undersurface there will exist, when either machine is in flight, a centerline of pressure extending lengthwise of the wing along the deepest partof the parabola, and about midway of the length of this center line ofpressure there is a point, indicated at m, which I call the focal pointof the wing. The two focal points of the wings are in the same verticaltransverse lane yy with the center of gravity 2 of the machine when thelatter is in flight, and the wings are so constructed and disposed thatwith a uniformly distributed wind impinging on each wing the windpressure and lift on that portion of each wing forward of its focalpoint x, that is,

in front of plane y e is the same as the wind pre sure and lift on thatportion of the wing to the rear of the focal point x, or to the rear ofplane y 'z It Will thus be seen that so far as the center of gravity isconcerned the lift due to the incident angle when the machine is flyingunder power, and the upward pressure on the wing occasioned whendescending powerless, is equally distributed to the front and rearthereof so that the wind pressure in either case does not tend todisturb the longitudinal balance of the machine. Further, it will beclear that with the machine balanced in this fashion with respect to thefocal points of the wings and its center of gravity, the incline of thetop of the region of compressed air on which each sloping wing rideswill compel the machine to move forward as it descends when it becomespowerless while pivoted control flaps D and D adapted'to be swung intopositive or negative angles with relation to the wind to steer themachin' both laterally and vertically. These flaps D and D are connectedby wires or the like 2 with control members 3 that are manually operatedby the aviator. No other rudders than the flaps D and D are necessarywith this form of my invention but it is desirable to provide the rearportion of the body B with a vertical keel 4.

In both forms of my invention herein shown the motor 5 is mounted withinthe body B with its crank shaft 6 crosswise of the axis of the latterand extending to the outside of said body. At'each end shaft 6 carries abevel gear 7 that drives a bevel gear 8 connected with a propeller 9."The propellers 9 aremounted on studs 10 carried by extensions 11forming part of the frame of body B.

In the form of my invention shown in Figs. 5 to 11, inclusive, each wingA and A" has secured to-it near its inner end an up- 'wardly extendingbracket 12 which is pivotally secured by means of a pintle 13 to a pairof transverse bars 14 rigidly secured to the body B. Also to the innerend of each wing there is pivoted the lower end of the stem 15, Fig. 6,which extends upwardly through a' plate 16 and a series of rubber washersprings 17 to a head 18 adjustably secured to said stem by' means ofnuts 19. The washers 17 are supported by the plate 16 which rests uponand is secured to two transverse bars 20 fastened to the frame of thebody B. The washers 17 serve as springs to yieldingly hold the innerends of the two wings against stops 21 secured to the under sides of thebars 14. I The wings A and A are provided, respectively, with flaps Eand E, each of which is made with stops 22 which engage with the underside of their wing to hold the flap against movement into i y a positiveangle with relation to the wind so that said flap can only be shiftedfrom a position parallel with the wind upwardly into a negative angle,or vice versa.

As shown in Fig. 10 each flap E and E is provided with arms 23 and 24,the former connected by a wire 25 or,v the like with one arm of a bellcrank 26 fulcrumed at 27 and having its other arm connected by a cord orwire 28 with the inner end of the wing of said flap. The other arm 24 ofeach flap is connected by a wire29 or the like with one arm of a bellcrank 30 fulcrumed at 31 and having its other arm connected by a cord orwire 32 with the inner end of the wing of said flap. 'When the outer endof either wing is swung upward on its pintle 13 as hereinafterdescribed, the downward movementof the inner end of the wing actsthrough connection 28, bell crank 26, connection 25 and arm 23 to swingthe flap upward into a negative angle and at the same time slack isgiven to the connections 32 and 29 through this downward movement of theinner end of the wing to permit of this movement of the flap. When theouter end of the wing swings down on pintle 13 to its normal positionagain the flap is returned to its normal position through the upwardmovement of the inner end of the wing acting through connection 32, bellcrank 30 and connection 29. It will thus be seen that so long as eitherwing occupies its normal position the control just described holds theflap of that wing parallel with the wind but that said flap isautomatically shifted into a negative angle with relation to the Wind.said flap to restore the wing to its normal position when the windpressure on the latter returns to normal. Thus when one wing receivesmore wind pressure than the other the wing flap thereof automaticallyopposes lifting movement of the wing and thereby automatically maintainsthe lateral balance of the craft against that excess wind pressure andat the same time makes it impossible for excess pressure concentrated atone or both of the wing tips to lift the rear of the machine, so thatsaid flaps also act automatically to maintain the longitudinal balanceof the machine at the same time.

For the normal speed of the machine there is a'definite normal windpressure on the wings for which the springs 17 of the latter areadjusted to hold the wings in their normal positions with the wing flapsneutral, and for continued horizontal flight there is also a definiteposition of the elevating rud- 4 When during flight under power bothwings receive a' sudden increase of wind pressure the rear ends of saidwings will be lifted relatively to the body thereby increasing the slopeof the wings, which tends to cause the machine to point downward, butsimultaneously with this movement of the wings the flaps E and E thereofare autotheir pivots from any matically shifted into proportionatenegative angles of incidence so as to produce a negative drag whichcounteracts this tendency .of the machine to dive when subjected toasudden increase of wind pressure in this fashion. The wings and flapswill act automatically in this fashion when the increased pressure isdue to asudden gust applied to any portionof the wings outside ofdirection which affects both wings slmultaneously, except when appliedfrom above upon the rear portions of the wings. In the latter case theeffect is the same as .a preponderance of Should the machine shown inFig. 5, etc.,

become powerless While in flight and start to sink, the upward windpressure on the wings will increase above normal and lift the wingsrelatively to the body B. This movement of the wings increases theirslope and thereby increases the effect of said slope upon the directionof movement of the machine with the result that the latter Will tend toglide forward as gravity causes it to descend this preventing rearwardmovement and producing a speed checkinglift. At the same time thisupward movement of the wings shifts the wing flaps E and E into negativepositions thus counteracting the tendency of the machine to dive underthe influence of the increased angle of the' slope so that in fallingthe machine will descend in a series of volplanes. whenever the forwardspeed of the machine reaches a definite rate where the pressure on thewings exceeds normal, the flaps will be operated and. produce sufficientnegative drag to the rear of the center of gravity to right the machineand check its descent after which it will again automatically pointdownward until its speed reaches that point again whereupon the checkingaction ofthe flaps will be repeated.

Assuming a normal, uniformly distributed and unvarying degree of windpressure on the wings and the wing flaps E and E as occupying theirnormal positions, the wind pressure efiects on that part of each wingback of the focal point will bethe same as on that part of the wing infront of the focal point because of the fact that the areas of these twoparts of each wing are made to be the same, and so long as thiscondition exists the machine will proceed horizontally under That is,

power without any alteration in the positions of its parts. Under theseconditions any increase in the speed of the machine which would be thesame in effect as an increase in the wind would only tend to cause themachine to ascend without disturbing its longitudinal balance.

A current of air striking a surface like the surface of a wing tends tospread laterally and in the case of an aeroplane wing of thekinddescribed the lateral movement of the air is considerable,particularlytoward the outer end of the wing. 'Heretofore only the movement of theair across the wing from front to rear has been utilized for producinglift. In accordance with my invention, however, I utilize. the lateralmovement of the air after it strikes the wing to produce additional liftby forming upon the concaved under surface of each wing a plurality ofrelatively small curved surfaces or cells 33, preferably parabolic inform, extending more or less crosswise of, or at right angles to, themain parabolic curve. 1 of the Wing. These supplemental parabolicsurfaces are herein shown disposed with their greatest depth of cambernearest the body of the machine so as to act upon the laterallyspreading air to exert a lifting force in addition to that exerted bythe main longitudinal paraboliccurve 1. In other words the mainparabolic concaved under surface of each wing is formed with crosswiseparabolic corrugations 33 which supplement the lift produced by the mainparabolic curve through the action thereon of the laterally spreadingair as it strikes the wing,

In addition to the elevating rudders C and C I provide a vertical rudderF for directing the machine laterally.

By making the flaps E and E so as to occupy only negative angles ofincidence I avoid the necessity of operating the vertical rudder F tomaintain the lateral balance of the machine when either of the flaps Eor E is thrown into anegative position.

The fulcrums 27 and 31 of each pair of bell cranks 26 and 30 are hereinshown as carried by a'vertically movable slide 34 made at its upper end.with a slot 35 to receive a guide pin 36 on the frame of the machine,and pivotally connected at its lower end to one arm of a bell cranklever 37 fulcrumed at 38 on the frame of the machine. The depending armsof the bell cranks 37 are formed withslots 38 into both of which extendsa pin 39 carried by an arm 40. Each slot 38 has a straight portiondisposed radially with respect to fulcrum 38 and a curved portion 41concentric with relation to the axis of a shaft 42 on which arm 40 isfixed. The curved portions 41 are oppositely disposed relatively so thatby swingmg arm 40 and pin 39 sidewise in one direction or the othereither bell crank can be maaeeo operated independently of the other. Theshaft 42 extends rearwardlythrough a yoke 43 which is pivotally mountedon trunnions 44 projecting from shaft 42. The yoke 43 has an upwardlyextending spindle 45 on which is rotatably mounted a sleeve 46 madehollow to receive said spindle and carrying a hand wheel 47 at its upperend. It will thus be seen that sleeve 46, spindle 45 and yoke 43 can beswung bodily fore and aft on trunnions 44 or that sleeve 46 can beindependently rotated on spindle 45. Also by swinging sleeve 46 sidewisethe operator can rock shaft 42 in its hearings to vibrate arm 40 andthereby operate either bell crank 37.

When either bell crank 37 is thus operated its slide 34 is movedvertically carrying with it the fulcrums 27 and 31 of bell cranks 26 and30 thereby manually producing the same relative movement between thebell cranks 26 and 30 and their wing as is pro duced by automaticmovement of the wing on its pintle 13. It will thus be clear that theflaps E and E, although automatically controlled and operated by theirwings, can at any time be manually operated.

The lower end of sleeve 46 is made with two depending arms 48 whoselower ends are in line with the axis-of trunnions 44. To said lower endsis connected the forward ends of cords or wires 49 which are connectedat their rear ends to a pair of arms 50 forming part of vertical rudderF. By partially rotating sleeve 46 on post rudder F may be swungsidewise to steer the machine laterally.

Projecting downwardly from yoke 43 is an arm 51 connected by a cord orwire 52 with one arm of a lever 53 fulcrumed at 54 on the body B. Theother arm of this lever 53 is connected by a cord or wire 55 with twodepending arms 56, one of which forms part v of horizontal rudder C, andthe other part of horizontal rudder C. The lower end of arm 51 is alsoconnected by a cord or wire 57 with two upwardly extending arms. 58, oneof which forms part of horizontal rudder C and the other of horizontalrudder C. By swinging the control member made up of parts 43, 45, 46, 47and 51 fore and aft on trunnions 44 said member will act through theconnections just described to swing the rudders C and C up and down ontheir pivots 59 to direct the course of the. machine vertically. Thelower ends of the arms 48 are arranged in line with the axes oftrunnions 44, as above described, .so that when the control member isswung fore and aft on said trunnions its movement in this direc-' tionwill not disturb the connections between said control member and rudderF.

The control above described is of the socalled instinctive type and is,l believe, more of this character than others heretofore proposed. Ifone side of the machine rises instinctively checks it by backwardmovement of the control member on trunnions 44. So also, should themachine tend to ascend the operator instinctively checks it by for- Wardmovement. of the control member on trunnions 44. In directing themachine toward the left the operator rotates wheel 47- in a left handdirection, and toward the right by rotating said wheel ina right handdirection.

What I claim is 1. An aeroplane comprising a body; two diagonallydisposed wings pivotally connected with the body at their inner ends sothat the outer rear end of each wing is movable relatively to saidbodyindependently of the other in a direction substantiallyperpendicular to the direction 'of flight and having their inner endsdisposed forward of the center of gravity of said body and their outerends disposed to the rear of said cen'. ter of gravity; means yieldinglyholding the. wings in their normal positions, and means for controllingthe direction of flight.

2. An aeroplane comprising a body; two diagonally disposed wings eachcomprising a rigid frame pivotally connected near its inner end with thebody so as to be inde pendently movable relative to said body, and eachwing normally sloping upward to- Ward the rear with their inner endsforward of the center of gravity of the body and their outer ends to therear of said center of gravity; means yieldingly holding each Wingagainst swinging upward from its nori and controlled by movement of thelatter relative to thebody, and means for control ling the direction offlight.

4. An aeroplane comprising a body; two diagonally disposed wings eachcomprising arigid frame pivotally connected near its inner end with saidbody so as to be independently movable relative thereto; means itsnormal position relative to the body; a

stabilizing flap movably mounted upon the outer portion of each wing soas to act both laterally and longitudinally; means through which themovement of each Wing relatively to the body operates the flap of saidwing,

.and means for controlling the direction of flight.

5. An aeroplane comprising a body; two diagonally disposed wings, eachwing being a rigid structure pivotally connected near its inner end withthe body so as to be independently movable relative thereto; andnormally sloping upward toward the rear; means yieldinglyjholding eachwing in its normal depressed position relatively to said body; astabilizing 'flap movably mounted upon the outer portion ofeach wingadapted to occupy only neutral and negative positions and to act bothlongitudinally and laterally upon the machine; means through which themovement of each wing relatively to the body operates the flap of saidwing, and means for controlling the direction of flight.

x 6. An aeroplane comprising a body; two diagonally disposed wings eachof which is a rigid. structure pivotally connected near erated.

its inner, end with said body with its inner end disposed forward of thecenter of gravity of the body and its outer end disposed tothe rear ofsaid center of gravity; means 'yieldingly holding said wings in theirnormaldepressed positions; stabilizing devices mounted on said wings inpositions to the rear of the center of gravity of said body andautomatically operated by movement of said wings; a rudder for directingthe machine up and down, and means connected with the rudder andstabilizing means through which said parts are mannally op- 7. Anaeroplane comprising a body; two diagonally disposed wings eachpivotally connected with the body so as to be inde-' pendently movablerelative thereto; means yieldingly holding said wings in their normalpositions; stabilizing devices connected with and operated 'by movementof the wings; a rudder for controlling the direction of flight; a singlecontrol member, and means connecting the control member with the rudderand stabilizing devices through which the latter are operated by saidmember-with provision for exclusive automatic control of the stabilizingdevices by the wings while said member is held stationary.

8. An aeroplane comprising a body; two I diagonally disposed wingsconnected with said body and sloping upward toward the rear; twonormally neutral planes each movably connected with one of the wingsnear the tip of the latter and adapted to be shifted back and forth fromits normal position and a negative position only, and automatic meansfor operating said planes to maintain lateral and longitudinal balance.

10. An aeroplane comprising a body; two diagonally disposed flexiblewings connected with said body; two normally neutral planes each movablyconnected with one of the wings near the tip of the latter and adaptedto be shifted back and forth from its normal position and a negativeposition only; means through which said wings automatically operate saidplanes, and means wherewith to manually operate said planesindependentlv of their automatic control by the WlIlgS.

11. An aeroplane comprising a wing having an under surface formed with amain para-v bolic curve whose chord is disposed longitudinally of themachine and with a multiplicity of parabolic curves whose chords aredisposed substantially at right angles to the chord of the mainparabolic curve.

12. An aeroplane wing havin its under surface made up of a multiplicityof-compound parabolic cells.

13. An aeroplane wing having its under surface made up of a multiplicityof compound parabolically curved surfaces.

In testimony whereof I have aflixed my signature in presence of twowitnesses.

WILLIAM STEVENS.

Witnesses: A

CLYDE L. Romans, 1 ARTHUR RANDALL.

